Features: 1.Self Generating: Wireless doorbell button is self generating, wiring free and battery free, saving energy and making it more convenient to use. 2.Waterproof Design: Mini wireless doorbell is waterproof, can adapt to various weather conditions to ensure long term effective use, sturdy and durable. 3.Strong Penetrating Power: Battery free wireless doorbell has strong penetrating power, can support through the wall use and long distance signal transmission. 4.Easy to Install: Self Generating doorbell a simple installation, convenient and time saving, don't need complicated wiring or complicated steps. 5.Multiple Purpose: Waterproof mini doorbell is not only a doorbell, but also can be used as a pager for babies and the elderly, pregnant women and other people. Specification: Item Type: Wireless Doorbell_x000D_ Material: Plastic_x000D_ Radio Frequency: 433MHZ_x000D_ Receiver:_x000D_ Voltage: US AC100-230V, Frequency: 50/60HZ, Power consumption: 0.25W PackageList: 1 x Emitter 1 xReceiver 1 xDouble Faced Adhesive Tape 1 x Bilingual Instruction